SoE 2003 > Biodiversity > 6.9 Aquatic harvesting

6.9 Aquatic harvesting

Most key fish stocks have been fully exploited, prompting the introduction of controls on harvesting

Significant quantities of aquatic resources have been harvested by commercial and recreational fishers over the past five decades. Exploitation levels were at their highest in the early to mid-1990s, with the number of fishers, the capacity of the fishing fleet and the annual harvest at or above sustainable levels.

Recent changes have reduced the number of commercial fishers, tightened the regulation of the recreational catch, protected key areas from overfishing, and promoted sustainable aquaculture. Despite these reforms, several species have experienced substantial declines. The harvest of a number of key fish stocks has fallen to even lower levels and the overall commercial fish harvest is currently 10–15% below the five-year annual average.

Further management actions are being taken to protect fish habitat, and rationalise and consolidate the NSW fishing industry and its production.

NSW Indicators

Importance of the issue

Overfishing poses a serious threat to the health of both marine and freshwater ecosystems and is an important pressure on aquatic biodiversity in NSW. Over-exploitation can lead to reduced biodiversity and even local extinctions. It is now widely recognised that lakes, rivers, estuaries and oceans can be fished out, with considerable economic and social impact (NSW Fisheries 1999).

Fisheries resources have a wide-ranging natural variability in population size, structure, condition and extent. Fluctuating fish populations and catches have also been attributed to human intervention through habitat modification, pollution and over-fishing. The variability of fisheries resources makes them difficult to manage. Insufficient information about the life cycles and ecology of fish has resulted in full or over-exploitation, especially of commercial species, across Australia (Yencken & Wilkinson 2000).

Estimated wild fish stocks

Fish stocks face pressure from a range of activities and need to be regularly assessed. Estimates of stocks of fish (and other aquatic species) help provide a measure of fishery productivity and the degree to which fisheries are sustainable. The data shows that the stocks of some species remain stable, despite significant harvest rates. Others, however, are experiencing decline.

Table 6.12 shows the status of various commercial fish stocks in NSW, using an assessment approach currently under development by NSW Fisheries. Data is not available for non-commercial species.

Table 6.12: Status of various NSW commercial fish stocks

Source: NSW Fisheries data, as at August 2002

Notes: Exploitation status:
Underfished: The stock may have the potential to sustain catches significantly higher than those currently being taken.
Moderately fished: The stock is thought to be fished at levels that would probably allow only limited increases in catches.
Fully fished: Current catches are probably sustainable and are at close to optimum levels.
Overfished or depleted: Current fishing levels may not be sustainable or yields may be higher in the long term if the fishing level is reduced.
Uncertain: There is little or no information about the status of this stock (no catch data or only very recent catch data).

In addition to harvesting pressures, freshwater fish species in the rivers of NSW have been declining because of impacts such as the construction of dams and weirs, which alters river flows, the removal of habitat, declining water quality and the introduction of foreign species (Harris & Gehrke 1997). In recent surveys conducted across the State by NSW Fisheries, 30% of species expected to occur were not recorded, indicating a general decline or disappearance of some species (Harris & Gehrke 1997; NSW Fisheries 'FishFiles' data). Another survey showed a decline in species diversity and fish numbers throughout NSW, with a corresponding increase in the introduced carp (Gehrke et al. 1995).

Fisheries catch

The total fisheries catch provides an indication of the pressure on native biodiversity from harvesting and the stability of the populations of exploited aquatic species. Managing and reporting on fisheries is complicated by the many populations which span the jurisdictional boundary between NSW and Australian territorial waters.

NSW has several thousand fish species and several hundred are harvested regularly by commercial and recreational fishers. Most of the commercial catch is derived from the State's marine waters (72% in 1999–2000), with smaller proportions harvested from estuarine waters (27%) and relatively minor quantities from inland waters (1%). Figure 6.5 and Figure 6.6 show the trend in the total catch for marine and inland fisheries in NSW since 1984–85.

Figure 6.5: Commercial marine fisheries catch

Source: NSW Fisheries data, as at August 2002

Figure 6.6: Commercial inland fisheries catch

Source: NSW Fisheries data, as at August 2002

Substantial changes have occurred in the State's marine fisheries. The commercial harvest from coastal waters for 1999–2000 was approximately 9500 tonnes, a significant decline from the peak catches of the early to mid-1990s. This fall can be attributed to a number of factors:

• changes in the management of fisheries resources and reporting arrangements between Commonwealth and State agencies as a result of offshore constitutional legislation
• greater regulation of the NSW catch
• reductions in the number of operators
• implementation of additional bag limits for recreational fishers
• an increase in the number of protected areas.

Like-for-like comparisons indicate that harvests of a number of key fish stocks are below the five-year average catch levels and several species have experienced substantial declines.

The figures on total catch do not include bycatch and recreational fishing. 'Bycatch' is the non-target species that are caught as part of a fishing operation. These fish are discarded because they are below the minimum legal size, of less desirable eating quality, are part of tag and release fisheries, or for ethical reasons. Post-release mortality may be a significant management issue given the number of unwanted fish (and other organisms) caught and released by fishers. Bycatch is not counted in the total catch numbers in Figure 6.5 and can be very large.

Recreational fishing is also not counted in the total catch figures and has only recently been recognised as having a significant potential impact on aquatic resources. Estimates from a recent national survey of fishing indicate that NSW recreational fishers catch around 13 million fish, 17 million prawns, crabs and lobsters, and 2 million bait fish each year (Henry & Lyle 2003). The total NSW recreational harvest was estimated to be about 30% of the commercial harvest, but the share of the resource varied among species. Several common estuarine fish species (bream, flathead and whiting) were harvested in greater numbers by recreational than commercial fishers.

Response to the issue

There are three main responses to address declining fish stocks:

• regulating fish harvesting so that less is taken
• establishing protected areas
• improving harvest efficiency to minimise bycatch.

There have been major changes in the management of fisheries in NSW over the past decade. Many of these are related to jurisdictional changes between the Commonwealth and State governments through offshore constitutional settlement legislation and the passage of the Fisheries Management Act 1994 (FM Act). Fishery Management Plans are being developed for all commercial fisheries, with restrictions on entry and/or operating under managed quotas. Stock assessments have been conducted for a number of fish species and plans are in place for a suite of scientific studies to complete the assessment of resources. In addition, a new catch reporting system was introduced in the late 1990s to coincide with the offshore constitutional changes and the declaration of Restricted Entry Fisheries under the FM Act.

Bag and size limits for recreational fishing have been reviewed and strengthened. In 2001 daily bag and possession limits that previously applied to 37 fish species were extended to several hundred recreational species. A general recreational fishing licence, also introduced in 2001, is generating funds to buy out commercial fishing licences, establish 30 recreational fishing havens, and protect and restore fish habitat. This is expected to reduce pressure on fish stocks and resolve conflict over fishing opportunities for recreational and commercial fishers.

Ultimately, about $20 million will be spent to buy back about 250 commercial fishing operations. Funds from the licences have also been used to develop aquaculture and implement a range of research projects to improve fish stocks and fishing.

The FM Act helps in identifying marine areas to be protected as well as a range of other fish and habitat protection strategies. Marine protected areas may include highly protected 'no take' sanctuary zones where fishing is not permitted, providing safe breeding areas and enabling preservation of key stocks (see Biodiversity 6.6).

NSW Fisheries is involved in projects to develop bycatch reduction devices for commercial and recreational fisheries. These devices have been introduced in a number of key fisheries, such as commercial prawn trawling. Research is also under way into minimising the mortality of line-caught fish discarded by recreational fishers.

Aquaculture (the farming of fish, molluscs, crustaceans and aquatic plants) has the potential to reduce pressure on demand for wild fish stocks, but also poses its own environmental risks. These include the spread of pollution and disease to nearby aquatic ecosystems and increased pressure on wild stocks of fish used as feedstock. Structures such as oyster racks and fish cages can also have impacts on marine life and bring hydrodynamic changes to estuaries. These problems will be addressed in environmental guidelines for the aquaculture industry currently being developed, together with whole-of-government regional sustainable aquaculture strategies.

Effectiveness of responses

There has been a significant effort over recent years to control fishing and stabilise the harvest of aquatic resources. The number of commercial operators has fallen from about 3000 in the mid-1990s to 1400 currently. However, it is too soon to measure the benefits for fish stocks from the reforms to commercial and recreational fishing.

Bycatch reduction devices have been successful in minimising the waste of resources in a number of fisheries. These devices can reduce the bycatch of some species by 90% while having no impact on the catch of targeted species.

The development of regional sustainable aquaculture strategies is helping meet the demand for seafood and hence relieve pressure on the State's wild fish stocks.

Future directions

The stresses on the current resources are likely to increase because of population growth, coastal development, technology and pollution. Government and the community will have to manage what is presently available for the benefit of current and future generations.

Government should continue to assist commercial operators to adjust their practices and ensure sound recreational catch controls are addressed through the preparation of management strategies and environmental assessments for all major fishing activities.

Government should also continue to expand marine reserves to protect key stocks.

Linked issues

2.1 Population and settlement patterns

4.1 Land-use changes

5.1 Freshwater riverine ecosystem health

5.2 Surface water extraction

5.3 Surface water quality

6.6 Aquatic ecosystems

6.7 Aquatic species diversity

6.8 Introduced aquatic species